Measurements of spatial reactant and product concentrations in a flow reactor using laser-induced fluorescence

Abstract

A system capable of measuring heterogeneous and homogeneous reactions inside cylindrical flow reactors is described. In this system, the laser-excited fluorescence of reactant gas molecules is used to measure the spatial concentration of these molecules down the length of a cylinder coated with a suitable catalyst. The laser beam can be placed either on axis or off axis of the cylinder to measure the gas distribution. From the spatial concentration and certain experimental parameters, the rate constant can be determined. This technique is more versatile than a gas sampling probe because the gas flow is not disturbed. Also, an instantaneous reading of the relative gas concentration and a high degree of sensitivity are obtained. This technique is applicable to most gases, but, for this study, it was used to examine NO2 solid reactions in polluted atmospheres.